Abstract : A series of flight tests was initiated by the Langley Research Center for the purpose of testing ablative cork as a lightweight thermal protection material. These flight tests were conducted aboard NASA flight vehicles in the low-heating-rate environment of the afterbody regions. The test conditions covered a range of altitudes to 482,000 feet and velocities to 17,900 feet per second. The test results show that cork can provide adequate thermal protection for a long-time, low-heating-rate environment. p4